Monopod head

ABSTRACT

A monopod head enables movement of an optical instrument relative to a longitudinal axis of a monopod in directions parallel or normal to the optical axis of the instrument and includes a robust braking system to control movement of heavy instruments.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Provisional App. No. 61/608,327,filed Mar. 8, 2012.

BACKGROUND OF THE INVENTION

The present invention relates to a head for a monopod and, morespecifically, to a robust monopod head enabling tilting of a mountedoptical instrument either parallel or normal to the instrument's opticalaxis.

A tripod provides unmoving support of a camera, binoculars, telescope orother optical instrument. This is particularly important whenphotographing with a long exposure time where even slight movement cancause blurring of the image. While a tripod provides excellentstability, a monopod provides better control of the instrument thanhandholding, particularly when using long, heavy telephoto lenses and amonopod is typically lighter, smaller and more portable than a tripod.The freedom of movement offered by a monopod's single point of supportmakes it easier to pan shots and visually acquire moving objects. Thecombination of mobility and stability offered by a monopod often makesthe monopod the support of choice for optical instruments in the fieldwhere monopods are commonly used by wildlife and sports photographers.

While a camera or other optical instrument could be attached directly toa monopod, the stability provided by the monopod is adversely affectedif the monopod is tilted to orient the camera or other instrument. Aball head is often used in conjunction with a monopod to enable tiltingof the instrument relative to the monopod. However, ball heads commonlyhave a restricted range of motion and the friction setting mechanism isoften not sufficiently robust to restrain instruments with long, heavylenses particularly when the monopod is moved. What is desired,therefore, is a robust head for a monopod that enables a large, heavyinstrument to be adequately restrained but easily tilted through a widerange of movement in either direction relative to the longitudinal axisof the monopod with the optical axis of the instrument either alignedparallel or perpendicular to the axis about which the instrument isbeing tilted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of a first assembly comprising a monopod, amonopod head and a camera.

FIG. 2 is an elevation view of a second assembly comprising a monopod, amonopod head and a camera.

FIG. 3 is a perspective view of the monopod head of FIG. 1.

FIG. 4 is a plan view of the monopod head of FIG. 3.

FIG. 5 is an elevation view of the monopod head of FIG. 3.

FIG. 6 is an elevation view of the right side of the monopod head asillustrated in FIG. 5.

FIG. 7 is a section view of the monopod head taken along line C-C ofFIG. 6.

FIG. 8 is a perspective view of a top for the monopod head of FIG. 3.

FIG. 9 is a plan view of the monopod head top of FIG. 8.

FIG. 10 is an elevation view of the monopod head top of FIG. 8.

FIG. 11 is an elevation view of the right side of the monopod head topas illustrated in FIG. 10.

FIG. 12 is a section view of the monopod head top of FIG. 11 taken alongline C-C.

FIG. 13 is an elevation view of the monopod head with a surface of aninstrument mount tilted normal to the lower surface of the head's base.

FIG. 14 is an elevation view of the monopod head with a surface of theinstrument mount tilted at approximately 45 degrees to the lower surfaceof the head's base.

FIG. 15 is an exploded view of an instrument mounting clamp.

FIG. 16 is a perspective view of a monopod head and a lever operatedclamp.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring in detail to the drawings where similar parts are identifiedby like reference numerals, and, more particularly to FIG. 1, a monopod22, sometimes called a unipod, is an elongate, single pole that iscommonly used to help support an optical instrument such as a camera 24,telescope or binoculars. Monopods commonly comprise multiple foldingsections or telescoping tubular sections 26, 28 that slide within eachother to enable the extension of the monopod from a retracted lengthfacilitating transportation and storage to a length useful for astanding user of an optical instrument such as a camera. Relativemovement of the various telescoping sections of a monopod is commonlycontrolled by twist locks 30, 32, 34 which are rotatable to release thesections for relative movement and to restrain movement of the sections.The monopod 22 is equipped with a foot 36 that resists slippage.

Steadying a camera with a monopod enables sharper images with slowershutter speeds than handheld shooting. The reduction of shaking in thevertical plane achievable with a monopod also reduces small randommovements of video cameras and sharper images with other opticalinstruments. A camera or other instrument can be mounted directly on amonopod but to enable acquisition of a desired image, the monopod oftenmust either be moved or tilted to reorient the instrument's optical axisor the camera's image capturing device. Tilting of a monopod adverselyaffects the ability of the monopod to steady the instrument. As aresult, monopods are often equipped with a ball head allowing somefreedom to tilt the instrument while enabling the user to keep themonopod more vertical for better stability. However, the universalmovement of a ball head which is useful on a tripod is of limitedutility when using a monopod because the instrument can be panned byrotating the monopod-instrument assembly 20 on the foot. Further, thefriction lock of a ball head can be problematic, particularly when aninstrument with a long, heavy lens is attached to the monopod. As theinstrument is tilted, the force required to restrain the ball in theball head varies which can make the friction exerted on the ball headinadequate to restrain the instrument in some attitudes or so great asto cause the lightweight monopod to move when the user attempts to movethe instrument relative to the monopod.

In the monopod assemblies 20 and 50 of FIGS. 1 and 2, respectively, amonopod head 40 is used to connect the cameras 24, 52 and the monopod22. The monopod head 40 enables the camera or other instrument to betilted relative to the longitudinal axis of the monopod with the opticalaxis of the lens 38, the longitudinal axis of the elongate lensassembly, either parallel to the axis about which the instrument istilted as illustrated in FIG. 1 or perpendicular to the axis about whichthe camera is tilted as illustrated in FIG. 2. With the monopod 22vertical for best stability, the camera can be tilted toward either sideof the monopod with the optical axis 38 of the lens parallel to the tiltaxis 78 to change the orientation of the camera's image capture devicefrom a landscape orientation 44A, to a portrait orientation 44B, 44C.Or, with the optical axis 38 normal to the tilt axis 78 the camera canbe tilted either “up” or “down” from an orientation perpendicular to thelongitudinal axis of the monopod 54A to respective positions 54B, 54Cwhere the optical axis of the instrument is parallel to the longitudinalaxis of the monopod.

Referring also to FIGS. 3-7, the monopod head 40 comprises, generally,an instrument mount 60 rotatably attached to a top 62 which is pivotallymounted on a base 64. The base 64 has a substantially T-shapedcross-section comprising a foot portion 66 and a stem portion 68 whichprojects normal to the foot portion and substantially parallel to thelongitudinal axis of the monopod when the head is attached to a monopod.The foot portion of the base is securable to the head of a monopod 22.Typically, a monopod is equipped with a threaded stud that protrudesfrom a mounting plate 46 at the end of the monopod and which isengageable with a threaded bore 69 in the mounting foot portion 66 ofthe monopod head's base 64. The monopod head is threaded onto theprotruding stud until the bottom surface 72 of the foot portion 66 ofthe base 64 engages the mounting plate 46 on the end of the monopod.However, the base of the monopod head could be secured to the monopod byother mechanisms. For example, a threaded stud protruding from the footportion 66 of the monopod head could be arranged for engagement with athreaded bore in the mounting plate on the end of the monopod. Inaddition, opposing edge surfaces 73 of the foot portion 66 of the base64 are flared for engagement with corresponding surfaces of a clampwhich can be secured to the end of the monopod.

Referring also to FIGS. 8-12, the top 62 has a generally U-shapedcross-section comprising a pair of substantially parallel, projectinglegs 92, 94 and a leg connecting portion 93. The projecting legs 92, 94include portions defining concentric bores 102, 104 and the top 62 ispivotally mounted on the base 64 by arranging a leg on either side ofthe stem portion 68 of the base and installing a shoulder bolt 74 in theconcentric bores 102, 104 in the legs and a corresponding bore 76defined by portions of the stem. The threaded portion of the shoulderbolt 74 engages an internal thread in a bore 104 in one of theprojecting legs and is secured, without deforming the legs, bytightening the shoulder of the bolt against a step 106 in the threadedbore. The top 62 is arranged to pivot relative to the base on a tiltaxis 78 having an orientation fixed relative to the base and coincidentwith the longitudinal centerline of the shoulder bolt.

The torque generated by the friction mechanism of a ball head is limitedby the short distance between the friction element and rotational centerof the ball and the limited amount of friction that can be attained withthe smooth ball. Pivoting of the top 62 of the monopod head iscontrolled by a brake mechanism comprising a brake bolt 80, frictionelements 82, 84 and a lock knob 86. The brake bolt 80 has a head 88which bears on a washer 90 in contact with an outer surface of one ofthe projecting legs 92 of the monopod head's top. The shank of the brakebolt 80 passes through a portion of each of the projecting legs 92, 94that defines a slot 96, 98 that extends in a semi-circular arc radiallydisplaced from the respective concentric bore 102, 104 for the shoulderbolt and through a portion of the stem 68 that defines a brake boltaperture 108. The lock knob 86 is threaded on the end of the shank ofthe brake bolt 80 opposite the bolt's head 88. The lock knob 86 has alarge diameter to facilitate the user's grip on the knob and operationof the brake. The lock knob includes portions defining an axial centralcavity 110. The lock knob 86 is secured against disengagement from thethreads of the brake bolt shank by a lock screw 112 that is in threadedengagement with a longitudinal bore in the shank of the brake bolt andwhich bears on a surface in the interior of the lock knob to prevent theinternal threads of the lock knob from disengaging from the externalthreads of the brake bolt. A lock knob cover 114 closes the open end ofthe cavity 110 in the lock knob.

When the lock knob 86 is rotated to draw the head 88 of the brake bolt80 toward the lock knob, the force exerted on the projecting legs 92, 94of the top by the head of the brake bolt and a spacer 116 separating thelock knob and the projecting leg 94 causes the projecting legs to deformand compress the friction material 82, 84 between the projecting legsand the stem portion 68 of the base 64. Rotating the lock knob in theopposite direction releases the tensile force exerted on the lock boltallowing the projecting legs to separate reducing the friction betweenthe top and the base and enabling the top to pivot on the pivot bolt 74.When the top pivots on the pivot bolt the brake bolt is displaced in theslots 120. As illustrated in FIGS. 13 and 14, the slots 120 in theprojecting legs extend at least the length of a semicircular arcenabling a surface 123 of the instrument mount 60 to be tilted throughangles of at least ninety degrees either side of a central position. Themonopod head can restrain instruments weighing up to 70 lbs. becausehigh friction is achievable between the top and the base and thefriction force is applied at a substantial distance from the pivot axis.

The leg connecting portion 93 of the top 62 defines a toroidal bearingsurface 122 that surrounds portions defining an upper aperture 124having an axis substantially normal to the axis 78 of the concentricbores 102, 104 for the shoulder bolt 74. An instrument mount 60,supported by a friction reducing bearing 130 engaging the bearingsurface 122 is securable to the monopod head by a bolt 132 passingthrough the upper aperture 124. On the other hand, the instrument mountcould be secured to the top of the monopod head by a bolt extendingthrough the body of the instrument mount and engaging threads in theupper aperture 124 or by some other means.

Preferably, the instrument mount 60 comprises a clamp having a clampbody 142 defining a threaded aperture 131 engaged by the bolt 132passing through the upper aperture 124. Referring to also FIG. 15, theclamp 140 includes a clamp body 142 and a clamp jaw 144. The clamp jaw144 is engaged with the clamp body 142 by a pair of clamp springs 146.The springs 146 exert an outwardly directed force on the clamp jaw 144.The clamp jaw 144 is secured in place by the combination of a clampscrew 148 in threaded engagement with the clamp body, a clamp sleeve 150surrounding the clamp screw 148, a clamp knob 152, and a screw 154. Theclamp sleeve 150 sets the spacing for the clamp knob 152 and pressesagainst the exterior of the clamp jaw 144. As the clamp knob 152 isrotated to release the clamp jaw 144, the clamp jaw will be pressedoutwardly by the springs thereby opening the clamp and keeping the clampjaw 144 in tension to maintain it in a suitable position. As the clampknob 152 is tightened on the threaded claim screw 148, the clamp jaw 142will be pressed toward the surface 158 of the clamp body closing theclamp and securing any plate or optical instrument (e.g., camera, videocamera, etc.) between opposing surfaces 156 and 158 of the clamp jaw andthe clamp body.

Referring also to FIG. 16, the instrument mount may also comprise aclamp 160 operable by a clamp lever 162 that includes an eccentricportion 164 that moves the clamp jaw 166 relative to the clamp body 168when the lever is pivoted about a lever pin 170.

A toroidal indexing ring 172 projects normal to the bearing surface 122of the top 62. The indexing ring comprises portions defining a pluralityof indentations 174. Preferably, the indexing ring includes fourindentations spaced at intervals around the ring with a pair ofindentations 174A, 174B aligned with the axis 78 of the bores 102, 104that receive the pivot bolt 74 and a second pair of indentations 174C,174D on an axis 175 normal to the axis 78 of the pivot bolt bores. Anindexing screw 176 with a secured indexing knob 178 is threaded into aradially extending aperture in the clamp body 142. The end of theindexing screw 176 proximate the indexing ring 172 is arranged to engagethe respective one of the indentations 174 and secure the clamp body indiscrete rotational positions relative to the top enabling the opticalaxis of the instrument to be aligned either parallel to the pivot axis78 or normal to the pivot axis.

The monopod head 40 provides a full range of motion for a monopodmounted instrument and includes a robust braking system to securelycontrol the position of the an optical instrument weighing up to 70pounds.

The detailed description, above, sets forth numerous specific details toprovide a thorough understanding of the present invention. However,those skilled in the art will appreciate that the present invention maybe practiced without these specific details. In other instances, wellknown methods, procedures, components, and circuitry have not beendescribed in detail to avoid obscuring the present invention.

All the references cited herein are incorporated by reference.

The terms and expressions that have been employed in the foregoingspecification are used as terms of description and not of limitation,and there is no intention, in the use of such terms and expressions, ofexcluding equivalents of the features shown and described or portionsthereof, it being recognized that the scope of the invention is definedand limited only by the claims that follow.

I (we) claim:
 1. A head for securing an instrument to a monopod, saidhead comprising: (a) a base securable to said monopod; and (b) a topsecurable to said instrument, said top arranged to enable pivoting ofsaid instrument relative to said base about a first axis and to enablerotation of said instrument about a second axis normal to said firstaxis, said first axis having an orientation fixed relative to said base.2. The head for securing an instrument to a monopod of claim 1 whereinsaid top is arranged for securing rotation of said instrument inrespective ones of a plurality of discrete positions.
 3. The head forsecuring an instrument to a monopod of claim 1 wherein said top isarranged to enable pivoting of a surface of said top in a firstdirection from a first orientation to a second orientation substantiallynormal to said first orientation and to enable pivoting of said surfacein a second direction from said second orientation to a thirdorientation substantially normal to said first orientation.
 4. The headfor securing an instrument to a monopod of claim 1 further comprising abrake arranged to enable selective altering of friction between saidbase and said top.
 5. A head for securing an instrument to a monopod,said head comprising: (a) a base securable to said monopod; and (b) atop securable to an instrument and attached to said base, said topincluding a surface arranged to pivot about a pivot axis in a firstdirection from a first orientation to a second orientation substantiallynormal to said first orientation and arranged to pivot in a seconddirection from said second orientation to a third orientationsubstantially normal to said first orientation, said base restrictingsaid pivot axis to a single orientation relative to said base.
 6. Thehead for securing an instrument to a monopod of claim 5 wherein saidsurface is rotatable about a rotation axis substantially normal to saidpivot axis.
 7. The head for securing an instrument to a monopod of claim6 further comprising an indexer arranged to secure said surface againstrotation in ones of a plurality of discrete angular positions.
 8. Thehead for securing an instrument to a monopod of claim 5 furthercomprising a brake arranged to enable selective altering of frictionbetween said base and said top.
 9. A head for securing an instrument toa monopod, said head comprising: (a) a base securable to said monopod,said base including a stem extending substantially parallel to alongitudinal axis of said monopod; (b) a top comprising plural legs anda leg connection portion including a bearing surface, said plural legsprojecting substantially normal to said bearing surface, each legincluding a portion defining a pivot aperture and a portion defining anarced slot displaced radially from said pivot aperture; (c) a pivot boltengaging said plural legs and pivotally securing said top to said stem;(d) a brake operable to selectively alter friction between a leg andsaid stem; and (e) an instrument mount rotatably supported by saidbearing surface.
 10. The head for securing an instrument to a monopod ofclaim 9 wherein said brake comprises: (a) a friction element disposedbetween a leg and said stem; (b) a brake bolt slidable in said arcedslot and including a head bearing on a first of said plural legs; and(c) a knob in threaded engagement with said brake bolt, said knobbearing on a second of said plural legs such that rotation of said knobalters friction between at least one leg and said stem.
 11. The head forsecuring an instrument to a monopod of claim 9 further comprising: (a) atoroidal indexing ring projecting substantially normal to said bearingsurface and comprising a surface having plural indentations; and (b) anindex pin radially movable in said instrument mount and engageable withthe ones of said plural indentations.